Loss Analysis of Wideband RF MEMS Shunt Capacitive Switch in T and Pi-Match Configurations

A wide bandwidth coplanar-waveguide (CPW) based RF MEMS capacitive shunt switch with pi-matched & T-matched having high impedance transmission lines is designed and simulated for broadband (18-40 GHz) application. The effects of variation in membrane width (50 & 70 mu m) of the switch and high-impedance transmission line length (300 – 600 mu m) between the switch structures on scattering parameters are studied. The variation in beam width has very little effect on return loss of the switch in up-state. The reduction in high-impedance transmission line length yields marginal improvement in return loss. In the down-state configuration, the return loss showed negligible change with the variation in beam width and high-impedance transmission line length. The isolation is found improved with the increase in beam width and high-impedance transmission line length in whole frequency range. Simulating the technical performance demonstrates the greater improvement in RF characteristics of the switch particularly in return loss in up-state position. In order to validate the obtained result, Artificial Neural Network (ANN) has been trained using ADS result. Comparison shows good agreement between ADS and ANN results.